A new study revealed that corticosteroid treatment in patients with chronic obstructive pulmonary disease (COPD) or asthma increases their risk of developing a specific form of lung cancer – squamous cell carcinoma. The study, “The use of corticosteroids in patients with COPD or asthma does not decrease lung squamous cell carcinoma,“ was published in the journal BMC Pulmonary Medicine.
The study, performed by Dr. Zhi-Hong Jian and colleagues from Chung Shan Medical University in Taiwan, used the Taiwanese National Health Insurance Research Database to identify more than 1.6 million individuals with recently diagnosed COPD or asthma. Among them, almost 800 had lung squamous cell carcinoma (SqCC).
Several researchers have pointed to the possibility that having an inflammatory lung disease leads to an increased risk of developing lung cancer. Corticosteroids — both inhaled and taken orally — are used as a standard treatment for inflammatory lung diseases, and doses are usually increased during exacerbations or flares. However, few studies have looked into the possibility that corticosteroid treatment might alter the risk of developing lung cancer in COPD/asthma patients, and those that have present conflicting results.
The research team decided to focus on SqCC since this particular type of lung cancer is common in the COPD/asthma patient population, accounting for 20 percent of the lung cancers in the U.S. Researchers used what is known as a nested case-control design, enrolling patients with a recently confirmed diagnosis of COPD or asthma. Some went on to develop squamous cell carcinoma during the study period (2003-10), and these patients were compared to the COPD/asthma patients did not develop cancer.
The team calculated a cumulative corticosteroid dose for each patient and found no link between the dose and risk of squamous cell carcinoma in women. In men, however, corticosteroid use, specifically when taken orally, was associated with an increased risk of developing squamous cell carcinoma. If the corticosteroid dose was increased during the three months preceding cancer onset, the risk seemed to increase even further.
The authors mentioned that smoking might explain the different results observed in men and women, because smoking is 10 times more common among men than women in Taiwan. The male preference to smoke might also explain why 87% of the COPD and asthma patients enrolled were men. Other exposures that might increase the risk of lung cancer were, however, not accounted for in this study.
The authors concluded by noting the association they found between corticosteroid use in asthma and COPD patients and lung SqCC, especially male patients, and the possibility of increased risk with recent corticosteroid dose increases. They argue for better lung cancer screening in COPD/asthma patients, especially those responding poorly to treatment.